Add opam

roles/ocaml/tasks/main_lin.yml

@@ -2,3 +2,14 @@
   apt:
     name: ocaml
     state: latest
+
+- name: Install opam
+  apt:
+    name: opam
+    state: latest
+
+- name: Init opam home
+  command: opam init --reinit --root=/opt/opam --dot-profile=/etc/profile.d/opam.sh --comp=4.14.2 -a
+
+- name: Install required opam packages
+  shell: source /etc/profile.d/opam.sh; eval $(opam env --root=/opt/opam --set-root --switch=4.14.2); opam install --yes ocaml-lsp-server odoc ocamlformat utop dune menhir